Implantable vascular access ports are used extensively in the medical field to facilitate the performance of recurrent therapeutic tasks. A typical access port comprises a needle-impenetrable housing having a fluid reservoir that is sealed by a needle penetrable septum. The access port also includes an outlet stem which projects from the housing and provides a fluid passageway that communicates with the fluid reservoir. The outlet stem is used to couple the housing to a catheter. Specifically, the vascular access port is attached to the proximal end of the catheter. The distal end of the catheter is placed into a vessel. The access port is generally implanted subcutaneously at a location that is easily accessible.
Once the vascular access system is implanted, a non-coring needle, e.g., a Huber needle, attached to a feed line may be used to access the implanted vascular access port, by penetrating the septum, to deliver a desired medication. Alternatively, bodily fluids can be withdrawn from the location where the distal end of the catheter is placed.
Many conventional access ports in use contain a single fluid reservoir through which medication can be delivered to a patient. Such structures can, however, be severely limiting to medical practitioners. For example, it is often desirable to deliver medications that are incompatible when mixed together in a single fluid reservoir prior to infusion into the body of the patient. Alternatively, it may be desirable to use one lumen to deliver medication to a patient and use a second lumen to withdraw blood samples for testing. In fact, some medical institutions have policies that require that one lumen of an implantable port is dedicated for infusion and the other is dedicated solely for the withdrawal of blood samples. Such plural functions cannot be performed through the use of a single reservoir access port.
Conventional dual reservoir access ports have been developed. A conventional dual reservoir access port typically comprises a port base having a pair of separate reservoirs formed therein: a medial fluid reservoir and a lateral fluid reservoir. Each of the fluid reservoirs has a corresponding access opening that is sealed by an individual septum. The individual septa are secured in place by a cap that engages the port base. In some other designs, a single septum (e.g., compound septum) can be used to seal both reservoirs.
An outlet stem housing a pair of fluid passageways projects from the exterior of the port base, which outlet stem may be between the pair of fluid reservoirs, or at the distal end of the access port and in-line with the two fluid reservoirs. When the outlet stem is placed between the fluid reservoirs, the fluid reservoirs are arranged side-by-side, and the outlet stem projects from a longitudinal side of the housing. This placement of the outlet stem causes the fluid reservoirs to be spaced relatively far apart, increasing the overall size of the access port.
During the implantation procedure for a conventional implantable access port having a single reservoir, a subcutaneous pocket is first created to receive and house the access port. This is done by making an incision in the skin of the patient at the intended implantation site for the access port. The access port is then inserted beneath the skin through the incision. The outlet stem of the access port is usually received within the pocket last, after the proximal end of the access port is placed in the subcutaneous pocket. A catheter is then coupled to the outlet stem of the access port.
To implant a conventional side-by-side access port, an incision must be made at the implantation site that is at least as long as the access port. Only in this way can the access port be received through the incision followed by the outlet stem. The longer the incision, the longer the healing process before the access port can be freely utilized and the greater the potential for infection or other complications.